jdbc with unicode

Seems lot of discussions have already been done to insert farsiinto the database. So we have some oracle + unicode veterans in thegroup.I am trying to do an insert of half width katakana characters intooracle 7.3.x. When I insert the unicode values of the double bytekatakana characters, it works fine but single byte (half width)katakana characters dont work fine. Some junk characters are insertedinto the database.Has anybody encountered any such problem ?